Characterization of distortions in electro-holographic image by A Shack-Hartmann wavefront sensor

The wavefront distortions in a digitally recorded HOE which has the property of a spherical mirror is measured with a Shack-Hartmann wave front sensor to estimate its functional performance. The performance is compared with those in the reconstructed image from Fresnel zone patterns which are displayed on DMDs of different pixel shapes, and with an analog type HOE and a Spherical mirror. The distortion distributions from these samples are not too different from each other. All are revealing spherical mirror properties, though the mirror quality is not the same. This informs that the HOE really work as a spherical mirror. However, the focused beam size of the HOE is much bigger than those of other samples.